Faster feeding of the sheets from a stack of sheets will increase the throughput of a printer. Therefore, it is desired to maximize the throughput of a printer by feeding sheets from the stack of sheets at the fastest rate possible. Exemplary of a method and apparatus for feeding sheets from a stack is co-assigned patent application U.S. Pat. No. 6,076,821, entitled “Method and Apparatus for Feeding Sheets,” issued to Embry et al., which is incorporated by reference herein.
When feeding sheets from a stack of sheets to a processing station such as a laser printer, for example, it is desired to feed the sheets as quickly as possible without a paper jam. To prevent a paper jam it is useful to prevent the sheets from overlapping. Thus a minimum gap must be maintained between adjacent sheets being fed to prevent the sheets from overlapping while maintaining a desired feed rate.
There are times, however, when paper does jam in the printer for various reasons such as slippage of the feed rollers on the media. The slippage may be caused by use of media with a smoother surface than anticipated. The slippage causes multiple sheets to stop in the paper path. The user must then clear the paper path with risk of damage to the printer or risk pieces of the media remaining in delicate areas of the printer, which may cause future failures. Current algorithms reportedly fail to detect the slippage, particularly of the first sheet picked.
Accordingly there is a need to prevent the jamming of multiple sheets of media by detecting slippage of the feed rollers on the media and, more particularly, detecting slippage of the feed rollers on the first sheet of media. Therefore a more robust adaptive pick algorithm is necessary.
It is thus an object of the present invention to provide a more robust adaptive pick algorithm that detects slippage and, in particular, slippage of the first sheet.
It is a further object of the present invention to provide a control algorithm for controlling the feed rate so as to prevent jamming multiple sheets of media in the paper path due to feed problems.
It is a further object of the present invention to provide a method to adjust feeding a selected type of media or a method that may be applied to a number of media types.
It is still a further object of the present invention to adjust the delay between feeding the individual sheets based on the feeding time of the previous sheet and, more particularly, the first sheet.